Pitcher Scouting: Hammel's success with Cubs powered by his slider

Thanks to his success in the last two years, Jason Hammel has added his name to the list of non-Chicagoans who have launched successful careers in the City of Big Shoulders (alongside the likes of Stephen Douglas, Cyrus McCormick, Daniel Burnham and even Al Capone). I wrote this about Hammel in this week’s pitching report after he put together one of his best weeks of the season.

Hammel must really love hot dogs without ketchup or deep-dish pizza, because everything he has done in Chicago over the last two seasons has worked. In 183 2/3 innings with the Cubs dating back to 2014, essentially a full season, Hammel is 13-7 with a 2.89 ERA, 3.09 FIP, 0.97 WHIP and 180 strikeouts.

No matter your preferred metric, Hammel has been a top-of-the-rotation starter, from both fantasy and real-life perspectives, during his time with the Cubs. This is quite remarkable for a pitcher who entered 2014, his age-31 season, with a career 4.80 ERA, 4.33 FIP, 1.44 WHIP, 16.6% strikeout rate, and 7.9% walk rate. Hammel has earned 5.0 bWAR over the last two seasons with the Cubs, a mark that typically ranks just outside the top 10 for a full season.

​Hammel made one significant pitch-usage change when he joined the Cubs in 2014, which is driving much of his success. During the first eight years of his career (including his nine-start season with Tampa Bay in 2006), Hammel never threw his slider more than 22.2% of the time. In 2014, he bumped his slider usage rate to 31.8%. This year, it’s up at 37.4%. The results are undeniable.

Last year, hitters cobbled together a .194 batting average and .270 slugging percentage with 88 strikeouts and a 15.7% whiff rate against Hammel’s slider. This season, they’re hitting just .168 and slugging .208. Hammel has 42 strikeouts and a 16.9% whiff rate with the slider. When you isolate for right-handed hitters, you find one of the most devastating same-side breaking balls in the league. Over the last two seasons combined, righties are hitting .186, slugging .239, and striking out in 36.3% of their at-bats against the slider.

The slider has also turned into a weapon against lefties, and that’s what Hammel really needed to elevate his game. In 2013, Hammel’s final pre-Chicago season, lefties racked up an .881 OPS against him. That fell to .691 last year and is down to .640 in 2015. Before joining the Cubs, Hammel had thrown his slider a total of 9% of the time against lefties in his entire career. Last year, he threw it 23% of the time, and they amassed an .091 isolated slugging percentage against it. This year it’s at 22%, and their ISO is .083. The offering has become a weapon Hammel can use to righties and lefties, in any count, and to both sides of the plate.

Hammel was very good last season, but he has been great in 2015. He has a 2.76 ERA, 2.93 xFIP, 0.89 WHIP and 76 strikeouts in 75 innings. His strikeout rate is up to a would-be career-high 26%, while his walk rate is a sterling 3.1%. As you would probably guess at this point of the column, his slider has a lot to do with his success.

Opposing hitters are swinging at more than one-third of Hammel’s pitches that miss the zone, up three percentage points from the previous career best he set last year. His four-seam and two-seam fastballs, the only other pitches he throws more than 5% of the time, both go for strikes at a minimum of a 70% rate. It’s the slider that’s inducing all those swings on pitches out of the zone. As such, his overall whiff rate is 11.3%, which would have ranked 12th in the majors last season, sandwiched between Stephen Strasburg and Madison Bumgarner.

Hammel struck out a career-high 11 batters in a win over the Marlins last week. He threw 50 sliders in that game, 31 of which were strikes and 11 of which were whiffs. In one tidy start, Hammel showed how he can use the exact same pitch in different ways and thus dominate with it being his only real breaking or off-speed offering.

Six of Hammel’s 11 strikeouts came with the slider as strike three. As you will see in the ensuing GIFs, Hammel goes to the slider in 1-2, 2-2, and 3-2 counts, and uses it to strike out righties Giancarlo Stanton, Marcell Ozuna, and J.T. Realmuto, and lefty Christian Yelich.

All this is well and good, you say, but what about Hammel’s Oakland detour last year? Remember, when he compiled a 4.26 ERA, 5.10 FIP and 1.29 WHIP? Doesn’t that prove there’s more pixie dust involved here than it seems?

It’s true that Hammel’s numbers in Oakland look terrible, but he basically had one terrible month followed by two good months with the A’s after the Cubs dealt him, along with Jeff Samardzija, for Addison Russell. In his first 17 innings with Oakland, which alarmingly covered four starts, he had a 9.53 ERA and 2.12 WHIP, with just 12 strikeouts against 10 walks. In August, however, he cut his ERA to 2.86, and in September it was down at 2.20. In those final two months of the season, a stretch that included nine starts and 50 2/3 innings, Hammel had a 2.49 ERA, 1.01 WHIP and 42 whiffs against 11 walks. If anything in his performance over the last two years is an outlier, it’s that brutal four-start stretch during his first month with the A’s.

Hammel’s superficial stats are glowing this year, and will probably get him to the All-Star Game if he continues at this rate. Even better, his peripheral numbers strongly suggest he is built to maintain this level of success.

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